SpamAssassin has configuration options to modify mail body, but they seem to be ignored.
- amavisd-new never modifies mail body or let SA do it. All mail (header) editing is done by amavisd-new and not by SA.

und im nächste Absatz:

Does SpamAssassin observe settings in its configuration file local.cf?
- This is related to the previous item. SA does observe all settings in its configuration file, but not all of them have effect, as amavisd-new does its own decisions based on spam score (hits) (so for example required_hits has no effect - use tag/tag2/kill amavisd-new settings instead), and does its own header editing, and body is never modified.